Protective sheet

Abstract

The present invention can provide a protective sheet, a protective sheet preventing curl generation in a laminated article formed by using the same and having excellent appearance, and a solar cell module formed by using this protective sheet. A protective sheet includes a weather-resistant film A, an adhesive layer 1, a film B, an adhesive layer 2, a film C in the stated order, the film C having a thickness of 60 μm or more, in which the width W A of the weather-resistant film, the width W B of the film B, and the width W C of the film C have a relationship of W A >W C >W B .

1 . A protective sheet comprising: a weather-resistant film A, an adhesive layer 1, a film B, an adhesive layer 2, a film C in the stated order, the film C having a thickness of 60 μm or more, wherein the width W A  of the weather-resistant film, the width W B  of the film B, and the width W C  of the film C have a relationship of W A >W C >W B . 
     
     
         2 . The protective sheet according to  claim 1 , wherein the ratio (W B /W C ) of the width W B  to the width W C  is 0.65 or more and less than 1.0, and the difference (W C −W B ) between the width W C  and the width W B  is 32 mm or less. 
     
     
         3 . The protective sheet according to  claim 1  or  2 , wherein the ratio (W C /W A ) of the width W C  to the width W A  is 0.70 or more and less than 1.0, and the difference (W A −W C ) between the width W A  and the width W C  is 80 mm or less. 
     
     
         4 . The protective sheet according to any one of  claims 1  to  3 , wherein the ratio of the thickness of the weather-resistant film A to the thickness of the film C (thickness of weather-resistant film A/thickness of film C) is 0.75 or less. 
     
     
         5 . The protective sheet according to any one of  claims 1  to  4 , wherein the tensile elastic modulus at 23° C. of the film C is 2.0 GPa or more. 
     
     
         6 . The protective sheet according to any one of  claims 1  to  5 , wherein the film B is a moisture-resistant film having a base material and an inorganic layer in the base material on at least one side of the base material and having a moisture vapor permeability of less than 0.1 g/m 2 /day. 
     
     
         7 . The protective sheet according to  claim 6 , wherein the inorganic layer side of the moisture-resistant film is laminated to the weather-resistant film A. 
     
     
         8 . The protective sheet according to any one of  claims 1  to  7 , wherein the adhesive layer 1 and/or the adhesive layer 2 contains a pressure sensitive agent. 
     
     
         9 . The protective sheet according to any one of  claims 1  to  8 , wherein the thermal shrinkage rate of the weather-resistant film A is 0.5% or more. 
     
     
         10 . The protective sheet according to any one of  claims 1  to  9 , wherein the protective sheet is used in a solar cell protective sheet. 
     
     
         11 . An encapsulating material-integrated protective sheet formed by further laminating an encapsulating material layer D on the film C side of the protective sheet according to any one of  claims 1  to  10 . 
     
     
         12 . The encapsulating material-integrated protective sheet according to  claim 11 , wherein the width W D  of the encapsulating material layer is less than the width W A  of the weather-resistant film and more than the width W C  of the film C. 
     
     
         13 . A roll-shaped article formed by rolling up the protective sheet according to any one of  claims 1  to  10  or the encapsulating material-integrated protective sheet according to  claim 11  or  12 . 
     
     
         14 . A roll-shaped article with a cover sheet formed by at least partially covering a part at which the weather-resistant film A projects from the surface of the roll-shaped article according to  claim 13  with a cover sheet having a deflection length of 70 mm or less and a load bearing dent of 0.1 or less, wherein
 the deflection length is measured in a condition in which 
 (1) a sample with a width of 20 mm and a length of 120 mm is collected, 
 (2) the sample is placed on and protruded from a platform so that the protuberance from the platform has a length of 100 mm, and then a 5 kg weight is added on the part of the sample on the platform to fix the sample, and 
 (3) how much the end of the part of the sample being protruded from the platform hangs down from the platform is measured, and this measured length x (unit: mm) is determined as the deflection length, 
 the load bearing dent is measured in a condition in which 
 (1) A 100 mm square sample is collected, 
 (2) the sample is placed on a glass plate with a thickness of 20 mm, a 0.5 g steel ball with a diameter of 5 mm is added on the central part of the sample, and a 2 kg load is further added on the steel ball, and 
 (3) The dent “d” in the sample (unit: μm) is measured, and the ratio “d/t” of the dent “d” to the thickness “t” (unit: μm) of the sample is determined as the load bearing dent. 
 
     
     
         15 . The roll-shaped article according to  claim 14 , wherein the conditions (a′) and/or (b′) are satisfied,
 the condition (a′) is deflection length of cover sheet/deflection length of weather-resistant film A≦2, and 
 the condition (b′) is load bearing dent of cover sheet/load bearing dent of weather-resistant film A≦2. 
 
     
     
         16 . A method of producing a protective sheet comprising the steps of:
 (1) forming a laminate X having an adhesive layer 1 on one side of the film B and an adhesive layer 2 on the other side of the film B,   (2) slitting both the ends in the width direction of the laminate X to form a laminate X′,   (3) attaching a weather-resistant film A having a width W A  being more than the width W X′  of the laminate X′ to the adhesive layer 1 so that both the ends of the weather-resistant film A project from the respectively corresponding ends of the adhesive layer 1, and   (4) attaching a film C having a width W C  being more than the width W X′ , of the laminate X′ and less than the width W A  of the weather-resistant film A to an adhesive layer 2 so that both the ends of the film C project from the respectively corresponding ends of the adhesive layer 2.   
     
     
         17 . The method of producing a protective sheet according to  claim 16 , wherein the laminate X having a release sheet 1 on the adhesive layer 1 and a release sheet 2 on the adhesive layer 2 is produced in the step (1), the release sheet 1 is peeled off after the step (2) before the step (3), and the release sheet 2 is peeled off after the step (2) before the step (4). 
     
     
         18 . The method of producing a protective sheet according to  claim 17 , wherein the step (1) has the steps of:
 (1-1) applying an adhesive layer 1 composition to the release sheet 1 and drying the adhesive layer 1 to form an adhesive layer 1,   (1-2) applying an adhesive layer 2 composition to the release sheet 2 and drying the adhesive layer 2 to form an adhesive layer 2, and   (1-3) attaching the film B between the adhesive layer 1 and the adhesive layer 2 to form a laminate X.   
     
     
         19 . A solar cell module formed by using the protective sheet according to any one of  claims 1  to  10  or the encapsulating material-integrated protective sheet according to  claim 11  or  12 .